Gear shifter



W. G. STEVENS, JR.

3o' 1919. Patented May. 239 w25/3b l I4 SHEETS-SHEET l.

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GEAR SHIFTER. `APPL|CATI0N FILED SEPT. a0. 1919.

Patented May 23, 1922.

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GEAR SHIFTER.

APPLICATION FILED SEPT. 30, I9'I9. l,417,21 3.

Patented May 2391922.

I4 SHEETS-SHEET 3;

W. G. STEVENS, JR.

- GEAR smrm. i APPLICATION FILED SEPT- 30| I9I9. L4l7,213. Patented May 23, 1922,

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W. G. STEVENS,-Jn. GEAR sH|FER.

l I APPLICATION FILED SEPT-30,1919. l'lg I 5 I4 SHEETS-SHEET l6.

Patented May 239 11922..

w fe. STEVENS, JR.

vGEAR SHIFTER.

I Y APPLICATION FILED sEPTyao. 1919. Llll Pamnted Many 23, 31922.

I4 SHEETS*SHEET 7.

w. G. STEVENS, JR.

GEAR SHIFTER.

APPLICATION FILED SEPT- 30, i919.

Patented May 23, w22.

I4 SHEETS-SHEET' 8.

vv. sfEw/fj, "1a. GEAR SHIFTER.

w y APPucATmN man sEPT.30.' |9l9. L4M A213@ .Patented May 23, 11922.

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w. G. STEVENS, 1R.

GEAR SHIFTER.

APPLICATION FILED SEPT- 30, I9l9.

Patented May 23, E922.,

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W/Tf/ESSES W /ZMM W. msm/ENS, Jn. GEAR SHIFTER.

APPLICATION FILED SEPT- 30, 1919.

I Patented May 23, E922.

I4 SHEETS-SHEET Il.

w. G. STEVENS, II.

GEAR SHIFTEH. APPLICATION FILED SEPT. 30, 1 919.

Pwten/d May 23, 1922.

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Wl /VESSES A WUMJEV@ l Patented May 23, 1922.

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W G STEVENS 1R GEAR SHIETER, APPL ATIOY FILED SEPT 30 919 qlglg,

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APPLICATION FILED SEPT-30, 1919. 1,417,213..

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Patented May 23, 1922.

uNrrl-:D srATes PATENT ori-*lic WILLIAM GRANT sTEvENs, JR., or WILLIS, TEXAS.

GEAR, -sHIrTEit i vTo all whom it may concern. l i

Be it known that I, WILLIAM GRAN STEVENS, r., a citizen of the United States, and aresident of Willisin the county of Montgomery' and State of Texas, or Sao Paulo, Brazil, South America, have made certain new and useful Improvements in Gear Shifters, of which the following is a speciiication. V

My invention relates to improvements in gear Shifters for motor vehicles; and it consists in the constructions, combinations Iand arrangements herein described and claimed. The foremost object vof my invention is to provide a gear shifting mechanism which is almost wholly actuated by` the exhaust gas of the motor, certain steps in the operation being accomplished-bv the brief use of elecltricity, alli of the functions of the speed changing mechanism being thus 'accom- -plished by simply actuating several push buttons.

Another object of the invention is to provide means in -gear shifting mechanism for `an automobile, for utilizing .exhaust gas' pressure torst neutralize the transmisslon gears, disengage the driving,clutch'f'andnally shift the gears to the proper combinat1on, in order to obtain the desired speed. 30 l.

A further object of the invention is to provide a gear shifting mechanism of the character described, in which the exhaust gas, the force of which'was expended in making a circuit gear shift, is expelled by the action of the'clutch spring.v

A further object ofthe lnventionis to provide'in the lexhaust gas line, apressure valve by means of which an approximately constant pressure is maintained for the operation of the gear shifting mechanism, regardless of the volume of exhaust gas discharged by the motor. A A further objectr of theinvention is to vprovide means for controlling thespeed ofj clutch engagement, said means comprising a regulatable exhaust gas valve operatively associated with the pressure valve .above referred to. y

' A`furthe-r Iobject of the invention is to.

p rovide instrumentalities for automatically dlsengaging and reengaging the clutch atl the proper time each time a gear shift is made.

A further object of the invention isto provide a mechanism for the purpose described and to be operated by iuid under yshifting mechanism,

diagram ofthe electrical apof the upper part'of Specification 0f Letters I atqnt .Patented MayJZS, 1922. i Application filed September 30, 1919. Serial No. 327,416.

Other objects and advantages will appear Ain the following specifications, reference being had to the accompanying drawings, in

Figure l isa plan view of thechassis of alintor vehicle showing the invention app 1e Figure is a diagrammatic perspective view showmg the I'n-ain parts of the gear -Figure 3 is a paratus, l

Figure 4 lis a plan viewwith parts shown in section, illustrating the co-relationship ofthe automatic gear shifting mechanism, the transmission gearing and the automatic A exhaust gas control,

Figure 5 is an enlarged view'shown in section of the'automatic gas control,

Figure 6 is a sectional view of the threeway valve in its second position,

Figure 7 is a vertlcal section of the valve,

Figure 8 1s `a plan view on a larger scale,

the gear shifting mechanlsm in Figure 4,

F igure'9 is a Section taken substantially on the line 9-9 of Fi re 4,

Figure 10 is a detail section' taken substantially on the line 10- -1O of Figure 4,

Figure-'11 is a cross section on the line 11-'11 of Figure 8,l

Figure l2 is a cross section on the line 12A-12 of Figure 1 1',

4Figure 13 is a perspective v1ew showlng the various parts of one of the lock reels 1n Figure 11 separated,

Figure '14 is a perspective view showlng more particularlyl the shifting frame that A cooperates with the transmission. gearing,

Figure 15 is a detail view ofthe toggle arms and mechanism for revolving the dualrevoluble shaft in either of twodirections,

Figure 16'is a diagram illustrating parts .that come into operatlon when the neutral1z` fing device isused,

ico

Figure 17 is a detail view of the mechanically actuated contacts that cooperate with the dual-revoluble shaft,

Figure 18 is a detail perspective view of the exhaust gas cylinder and the retractor spring which returns the piston in the cylinder, s

Figure 19 is a detail sectional view, illustrating how the retractor spring remains under tension to keep the piston normally atthe extreme front end of the gas cylinder,

Fi ing t e actions of the gear shifting piston in the gas cylinder,

Figure 22'is a diagram showing how7 the clutch spring assists in returning the piston in the gas cylinder,

F igure'23 is a detail View showing how a serpentine pipe or coil may be used 1nstead of the straight pipe between the pres sure valve and gas cylinder, t

Figure 24 is a diagram of Aan improved brake mechanism tol be used in connection with the gear shifter,

Figure 25 is a perspective View of the brake engager cylinder, and

Figure 26 is a detail sectional view of said cylinder, illustrating the action of the piston on the fluid in the cylinder.

Generally stated, the improved gear shifting mechanism is to be used on automobiles or other-vehicles having a three speed forward and a one speed reverse selective type of sliding gear transmission mechanism. The three maj or elements of the gear shifter comprise a gas pressure cylinder; three valves for controlling the exhaust gas flowing to and from the gas cylinder; and variousmechanisms dependent on the motion of a rack piston rod of a piston contained in. the gas cylinder.

This gas cylinder and its icompanion mechanism takes up'but very little room .on the chassis of the automobile. -The entire apparatus can be enclosed in a casing measuring approximately 30 inches long and 5 inches square, the actual size ofcourse depending on the dimensions of the mechanism on the inside, which in turn is subject to some .variation according to the slze of 'the transmission gearing it is called upon i to shift.

In Figures 1 and 4, thevusual transmission mechamsm 1sV situated in a casing 1. The shifting of the various gears 1n this casing is done altogether by the power fur-4 nished by exhaust gas in the conduit ,2 from the automobile engine, which gas at certain times is diverted by the three-way valve 3 into the pressure regulating valve 4.

From here the gas is conducted through a. relatively long pipe 40 to vthe exhaust. gas cylinder 5 ofthe automatic gear shifting mechanism 6. This relatively long pipe 4() may be serpentine or coil shaped, as at 40` res 20 and 21 are diagrams illustrat-' in Figure 23, if' desired. Upon introduction of the exhaust gas into the cylinder 5,

the piston 7 is moved forwardly and its motion is finally transmitted to the shifting shaft 8 which has such connection with the gears in the transmission case 1, that they are shifted either forwardly or backwardly to obtain the desired result.

The foregoing is a very brief statement of what is actually accomplished, and the operations may be more specifically reduced to the following;-(1) The gears being in neutral, to be shifted into first speed and vice versa. (2) The gears being in lfirst speed,l to be shifted into second and vice versa. (3) The gears being in second speed to be shifted into third and vice versa. (4) The gears being in neutral, to be shifted into reverse and vice versa. (5,) The gears lbeing in second speed to be shifted into neutral. (6) The gears being in third speed, to be shifted into neutral. All ofthese operations are controlled by the electrical apparatus in Figure 3, and of necessity the paths of the various circuits, the various devices that they operate and the resultant actions on the mechanical parts, must be described in the order above outlined.

Operation of gear shift (1 The three-Way valve motor 9is thus enerf gized and its pinion 10 rotates the quadrant l1, turning-the three-way valve 3 so that the condu1t 2 is placed in communication with the pipe 12 which leads into the pressure valve 4. The turning of the quadrantY 11 places the spring 13 under tension, and the tension of this spring-.operates to return` l the valve 3 to its original position when its funct1on is fully performed and the motor 9/ 115 is cle-energized. The exhaust gas initially discharged into the valve 4 behind the valve piston 14, is conducted through the relatively long pipe 40 tothe gas cylinder 5 where it drives the actuating piston 7 forwardly.

The rack 15 of the piston rod 16, turns the gear 17 in clockwise direct-ion, so that lthe pinion 18 on the same shaft 19 revolves the clutch-pedal gear20 in a counter-clockwise direction. A clutch cable 21 is joined at one end to the gear 20 lby the link 22, and atwthe other end` to the clutch-pedal 23. When the gear 20 revolvesl as stated, the clutch-pedal 23 is operated to throw the clutch 24 on the shaft 25 out vagainst the tension of the usualx clutch spring 25l indicated in dotted lines in Figure 23. The' movement of the clutch-pedal and clutch opposite to the pinion '18, to which the cable v 110, running over the guide pulley 111, is

f attached. The other 4end of this cable is secured to the retractor spring 112, which is adjustably mounted at 113 onany convenient part of the frame. Now as the shaft 19 is rotated, as described, the retractor spring 112 is put under tension, at a subsequent period to assist in returning the piston 7 to the normal position in the gas cylinder 5. The combined efforts lof the clutch spring v25a and retractor spring 112 thus expels the gas from the gas cylinder 5, through a clutch valve 62 which has a minute orifice, the size of which controls the speed of engagement of the clutch 25.

In Figure 19, the piston 7 is shown to have returned to' the normal position, at

which time it is held in engagement with the stop 114 by the tension of the retractor spring 112. This spring is so adjusted that v when the piston 7 is at the normal pom'tion, it

'will not be entirely contracted, thereby holding the piston 7 against the stop 114 and preventing the jarrin of, the automobile'from moving the piston forwardy and shifting the associated parts out of a justment. Of course the stop 114 may be replaced by any other suitable means, that is to say, the

piston 7 may beso arranged as to engage the Y adjacent end of the cylinder 5, but in the present instance the stop `114 is merely shown to prevent closure of the gas pipe 4 0 which discharges adjacent to 'the jamb nut -at the end of the piston 7L l Upon energization of 'the clutch magnets R, the lock plates 27 were mutually attracted so as to bind the teeth 28 against the hub 29 in readiness" to .enter the recesses 30 in the initial subsequent rotation of the hub." rlhe hub 29 is part of a lock reel to which one end ofthe shifter cable is attached and partly wound. A part of the lock'reel shaft 33 is square and the ends are round.y The shaft is fixed and does not rotate. i

A spring hub 34 is Xed on the square part of the shaft 33. rA coil spring35 is lfastenedl at its respective ends to the .hub 34 and" the lock reel 31, and is thejmeans that ,Y permits the cable 32 to be paid out under on theengagement of the shifter arm 36 with the cable on its upward movement. The shifter. arm is carried by the shaft 37 on which thegear 20 is mounted, and as the vgear 20 rotates in the counter-clockwise direction previously referred to, the arm 36 'of course presses upwardly on the cable 32.

pivoted thereto one of a pair 'of toggle arms 44, 45.V Normally the toggle arms are disposed in the downwardly inclined Vposition indicated in full lines in Figure 15. The dual-revoluble shaft 46 is turned'in one direction or the. other, accordingly as the' toggle arms are positioned.

The toggle arms 44, 45 bend downwardly under the influence of the pressure of the rack piston rod 16 against the block 42, and the shaft 46 is revolvedlin a counter-clockwise direction. This motion is transmitted through gears 47, counter-shaft48, gears'49 and shifting shaft 8, to the shifting arm 39 which pulls the rod 40 forwardly, moving the gear 5() into engagement with the first 4speed gear51 and thus obtaining the first' speed. l

Means is provided for setting the toggle arms 44, 45 in readiness for the first action in the event they may be in positions other than that shown in full lines in Figure 15. This means consists of a crank 52 on the end of the shaft 37, which engages and moves the trip arm 53 of the setting rod 54 rearwardly against the tension of the spring 55. The rod 54 has an arm 56 with a flexible connection 57 to the arm 58 of the dual-revoluble shaft 46. When the connection is straightened, the arm 58-is pulled into the horizontal position, and in this position the toggle arm 45 is inclined downwardly. The

gears in the transmission case 1 are by this means brought to the starting or neutral positions. If desired, a roller may be placed on the end of crank 52 so that it willfengage the trip arm 53. y

A spring 59 between the free end of the pivoted trip 53 and. the rod 5.4 on which it is mounted, permits the crank 52 to move under the trip arm on the reverse movement when the actuating piston 7 and rod 16 return. The piston 7 is returned automatically by virtue of the spring 112 in Figures 18 and 21. The-movements of the piston 7 lare clearly illustrated in Figures 2O and 21,

wherein it is seen that when the motor-coni termed the trolled valve 3 is opened to the pipe 12, exhaust gas enters the gas cylinder 5 and forces the piston 7 forwardly, at the same time touching the spring 112.

When the valve 3 is closed to the pipe 12, upon de-energization of the actuating motor 9 as appears more fully below, the tension of the spring 112, assisted by the spring 25a of the clutch mechanism, reacts on the piston 7, forcing the gas out of the cylinder as shown by the arrows in Figs. 21 and 22.

It is at this time that a valve 62, properly clutch valve, comes into use. This valve is located in' a relatively small pipe 60 which leads from the automatic pressure valve 4 to the exhaust gas conduit 2. The valve 62 is of the plug type, the plug having a minute orifice 62, either the size `of which or the position of the valve governing the'speed with which-the clutch 24 moves into engagement.

In this connection the mode of operation ofthe automatic pressure valve 4 may be described to advantage. This valve consists of a cylinder with a'plurality of apertures 4?, in annular series. Springs 61 are connected .between a suitable bridge or spider 61a and 'the arm 61b at the end of the piston rod 14a.

These springs are adjustable in tension by the means 61c so that the valve can be regulated to operate at any desired pressure. Ordinarily, these springs are adjusted to operate at a pressure of approximately nine pounds above atmospheric pressure, in other words, when lexhaust gas comes in at a greater pressure than desired, the piston '14 moves outwardly to uncover one lor more series of apertures, permitting the excess gas to escape to atmosphere while the remaining gas flows through the pipe 40. through the cylinder 5 to actuate the piston 7.

Returning now to the time when the valve 3 is closed ofi" as in Figure 21. The piston 7 moves back by means ofthe clutch spring 25a and the spring 112, as already explained, forcing the spent gas out into the exhaust gas passage 2 via the pipe 60 and valve 62. Lf ythe orifice of the valve 62 is very fine, or if the valve is of such a nature that itis capableof adjustment to present a fine orilice, then the gas will escape slowly and consequently the springs 25 and 112 will function slowly, thereby causing the clutch 24 to` re-engage slowly.

The de-energization of the motor 9, by which. act the `valve 3 was returned to the original position, was referred to above. The motor 9 is (le-'energized when the crank i' 52 is continuing its first rotation, engages and closes, the normally open contact E. Current then flows from the positive Wire '(Z into the branch it, through magnet III,

lamme though momentarily, attracts armatures e and Z, opening contacts e, f and closing contacts i, Z. The momentary closure of contact E is sufficient for the subsequent action that must take place through the closure of the contacts z', Z. When the dual-revoluble shaft 46 was rotated toward the left, the contact arm 63 pressed contact E into engagement and completing a circuit from positive wire d, wire l1., magnet III, contacts z', Z, wire m, solenoid magnet II, wire and from thence to ground. v

The solenoid magnet II being energized draws the core G downwardly so that contacts I-I2 are made. This contact is held by the engagement of a recesses of the core. ontacts H2 thus'hold even after contacts E and E are broken.

Operation of gem' shift (2). Upon the shunting of the current from the n to contacts E" siring o in one of themotor 9 by the closure of the contact E in f the manner explained immediately above, the motor 9 was stopped,the spring 13 operated to return the three-way. valve 3 and in due course the actuating piston 7 returned to its original position.

The pedal is now momentarily released and immediately again depressed. This action characterizes each be observed in the descriptlon of each operation. The push button A is not depressed.

Magnet III became de-energized and the armatures e and Z returned to their original" gear shift as may p Crank 52 pushes the setting rod 54 rearwardly, straightening the loose connection 5.7 and pulling the toggle yarms 44, 45 to the original full-line position in Fi ires 9 and 15. -The continued rotation of t e Ashaft37 causes the arms 36a to engage the cable 64 and pull thereon in the direction of the arrow in Figure 2, thereby rotating the sleeve 65 to which the arms 45 are attached,

in a clockwise direction. The toggleY arms are thus set` into the dotted line position in readiness for the subsequent operation of the rack piston rod 16.

Under other circumstances the cable 64 y could not be pulled in the manner stated. In the instance of the second gear shifting operation, however, the energization of the magnets R2 -caused the lock plates 27a to toward the left; through the intermediate lock the hub 29a of .the second lock reel 312, andl thus prevent the cable 64 from paying out. The operation of this second' lock reel -is identical to that of the first and further description is thought unnecessary.

The piston rod 16 soon engages the toggle block 42, pressing' on the toggle arms and bending them upwardly so that the dualrevoluble shaft 46 is now rotated towardthe right and the shifting shaft 8 is rotated gear connections. The operation of ,restoring theftoggle arms 44, 45 to the original full line position through the action ofthe crank 52 and before the cablel 64 operated to convey thearms intoI the dottedline position, served to counter-rotate the shaft 46 so .that the shifting arm 39 which inthe first gear shifting operation was in engagement with/the rod 4Gb and inclined toward the right, was moved `toward the left. The gears 50, 51 were thus engaged and the shifting arm 39 sprang over to the rod 66 by virtue of the spring 67.

The shifting arm 39 cannot disengage the rod b when inclined either forwardly or rearwardly, because of thestructure of the bell-mouth 68 of the rod. This bell-mouth is made in such a way that .not until the arm reaches the `vertical position, is it free to disengage by virtue of the spring 67.

complished thus Besumingnow the second gear shifting operation,v the movement of the lshifting arm 39 toward the left brings the gear 69 in the clasel 1 into engagement `with the second speed gear 70, since it must be remembered the arm 39 is now in engagement'with the -shifting rod 66.- As the crank 52 continues its second rotation it eventually closes contacts E whereupon current is shunted from the motor 9 over wire h, magnet HT, contact z', wire j, through E to ground wire k. The motor 9 thus stops and the actuating piston 7 1s returned to the starting position. The energization of the magnet III now effects the closure of contacts K2 and theseparation of the contacts H2. This isae- The contacts E2 are closed by the arm 63 when the shaft 46 isA krevolved to the right in the second gear shifting operation. This contact being established, current Hows from the battery over wires d and z., through magnet TH, contacts 2' and Z, wire m, solenoid magnet T and over wire s to ground. i Y

By this means the core Cr is drawn upwardly so that contacts K3 are made in readiness forthe third gear shifting operation.

Contacts K3 remainfin engagement by the dropping of thel spring 0 into theh lower re- `cess of the central part of the core. Reverting to the sleeve 65, itis to be observed that the sleeve has a recess 71, which is" occupied by a pin 72 on the shaft 46. This arrangement permits certain necessary free motel-nent of the sleeve without affecting the shaft.,-

nets R or R2.

The actuating piston 7 is again moved forwardly, the crank 52 ,operates to neutralize gears and also to restore the toggle arms 44,

45 to the former full line position and when the block 42 is finally engaged by the rod 16,

the dual-revoluble shaft 46 is rotated toward the left and the shaft 8 is rotated to the right. The shifting arm 39 thus moves the rod 66 forwardly to engage the clutch faces 73', thus obtaining the third or full speed.

Current is shunted from the motor 9 by the closure of contacts E. These are instrumental each time in stopping the motor. Contacts E are closed by the arm 63 in the rotation of the shaft 46 toward the left, and the current initially flowing to ground throu h contacts E, now traverses the path t rough solenoid H to ground through the closed contacts i, Z and E. Contact H2 is thus made but performs no immediate function. Contact H2 is made so that when the pedal'B is again depressed, lthe gears will be shifted back intosecond.

Operation of gem' shift `(.4).

The crank 52 in the first part of its movement in every gear shift, restores the toggle arms v44, 45 to the original full line position and so neutralizes gears. The operator now desiring to shift from neutral into reverse, pushes the button R3 and depresses the pedal B. Current then flows fronti-the. battery through the motor 9, through contacts e and f, magnet IV, clutch magnets R', wlre g, through the reverse contacts beneath the button R3, over wire u and through clutch magnets R2 to ground.

Both clutch magnets are thus energized and consequently both cables 32 and 64 are pulled in the direction of the arrows in Figure 2, when the shaft 37 revolves toward the left by virtue of the rack rod 16. The shifter arm 39 is thus conveyed to the second rod 40b and the toggle arms 4 4,- 45 are set into the original full line position. The pull of the cable 64, however, presently resets the arms into Athe dotted line Operation of gea-r shifts (5). It has been explained under headings (1),

(2) and (3), how the various increases ofl speed are obtained from neutral to third. Neutral is arrived at when operating in the second speed in this manner. The neutralizing device illustrated more" particularly in Figures 2 and 16 is employed only on the occasion of shifting Vthe gears into neutral from any speed, and also to neutralize gears when goingdirectly from one speed to another. l

The spark controlling rod 75 is turned by the operator so that the cable 76 pulls the primary contact arm 77 over into the path of the'v crank 52 and into'y the dotted line position lin Figure 16. The normally open contacts S thusclose and current flows from'the battery C over wire W through contacts Sand wire w to contacts v. These contacts are now 'closed since the arm 63 is stilleitlier in engagementl with contacts E2 or inclined to that side, because it must be remembered, the gears are now in sec- 4 ond'speed.

Continuing the How of current, the motor 9 is energized. Foot pedal B does not enter --in operation (5). vFrom the motor the cur= rent flows through contacts e, and f, wire p, contacts'g, Wire 7 to core G, and through the thia l closed contacts K2 to ground via thedwire'- t. The motor thus operates to advance the actuating piston 7 and turn the shaft-37 so that the crank 52 returns the togglearms 44, 45 to the original full line position through-the medium of the connectons'56, 57 and; y58..,'Thegea'r 69 is thus disengaged..j.from. th'e gear 70.

The Inotori'fisv not permitted tooperate long enough, Qi'rather to leave the valve 3 open long enough to let the piston 7' make such a-,stroke las will carry the 1rod 16 into7 engagement with the'toggle block 42, but the current to the motor is` shu'nted in the closing of the secondary contacts `S2 by the movement of the secondary contact arm 78. This arm is mounted on the stub shaft 7 8a, bywhich the primary vcontact arm 77 is fixedly carried, and on which the arm-78 has a pin and slot connection 79 as clearly Fshown in Figure 16. The action of the arm 78 is retarded by reason of the recess and pin connection designated, between the two arms mentioned.

Also,.if desired, a cable may be used between arm 78 and rod 142 of valve4, so that, when arm 78 is rotated the piston is moved and the small apertures y4perm1t escape of gas. Pressure is thus suddenly reduced on piston 7 and rod 16 is brought to rest directly after neutralization and before engagement with toggle block 42.

When contacts S2 are closed, current Hows over the Wire h, through magnet III, contact z', Wire j, Wrew, and through contacts S2 to the ground. The motor 9 is thus stopped before the crank 52 reaches contacts E and before the rack rod 16 hasA an` opportunity to act on the block 42.

Whnthe gears are in third speed, the contacts H2 are closed. The toggle arms' 44, 45 are in the extreme downwardly inclined po sition or to the left, and the shifting arm 39 leans toward the right. Upon closure of contacts Sby the operation of the rod 75, current is made to flow through the motor 9 -to actuate the piston 7, thereby in turn rotating the crank 52 to bring the toggle arms vto the first or starting position. This action shifts the clutch faces 73 apart.

When contacts S2'are closed, in the manner already explained, the current is diverted ,from the motor. Contacts S2 are closed, just' before contacts are opened by the arm 63, since, it must -be remembered, that the contacts@ are held open by the arm 63 atthe neutral point. The opening of contacts fz. prevents flow of current to wire d 'from Wire fw, and consequently the neutral circuit is Theforegoingdescription' deals altogether 'connection with 'this the various cooperating parts have been brought in so that both the construction and operation might 'be easily "with the operation of the mechanism, and in 110- understood. There are other-details of c on- I vstruction to which attention is directed. In -order to prevent the escape of gas 'from the rear to the front of the cylinder 5 'when` gthe actuating piston 7 is moved forwardly,

novel packing device is embodied in the npis- -ton and consists of pair of flexible Washersg -80 thatarexbent over the plates 8l at the rear. fTheseplates in turn are curved at the periphery and perfor-ated at 82 so that .gas

may get behind the curved parts of\ the plates, occupy the spaceptherebetweeen and the adjacent washer Vand thusA force vth'e Washer against the cylinder and prevent leakage. r

The same structure is provided at-each side of the piston.v Disks. 83-vserve to hold and support the Washers, and all are secured- 

